View Full Version : Process Gateway: General Interrogation (T100) to IEC870 Slave

3rd December 2019, 20:58
Dear Support Team:<br><br><br>I noticed that it is necessary to send general interrogation (T100) to the Process Gateway IEC870-104 Slave in order to receive spontaneous values, but is it possible that IEC870-104 Slave sends spontaneous values automatically after successful connection (or re-connection) to the IEC870-104 Master?<br>Is it mandatory to send always general interrogation to the slave in this case? or Does it depend on Master or Slave configuration?<br><br>I really appreciate your help.<br><br><br>PD: zenon Energy Edition 8.00 SP0 Build 52082<br><br><br>Best regards,<br><br>Jose Alejandro

4th December 2019, 14:27

According to the 60870 standard, indeed the General Interrogation is mandatory at the beginning of the communication.
Thus, after the startup of the Slave, it will wait for a certain time (called the T1 timeout) and if it never receives a GI from the Master, it closes the session.
Spontaneous data changes will be sent by the Slave only for data points responded in the GI.

Best regards,